FLOWSIC100 Operating Instructions
Gas Velocity Monitor
Assembly and Installation
56
©
SICK MAIHAK GmbH · Germany · All rights reserved
88012513/03-2008
3.1.1 Determining the Measurement and Mounting Location
Flow profile
The accuracy of measurement is subject to the flow conditions and the position of the mea-
surement axis. Significant changes in the cross-section, duct curvatures, fittings in the duct,
air dampers, or inlets can cause profile deformations or turbulence that will impair the re-
sult of the measurement. To ensure that the measurement is as accurate and trouble-free
as possible, the gas flow at the location of the measurement should be homogeneous (see
Fig. 3.1).
Regular, unimpeded profiles are most likely with long inlet and outlet sections. The longer
the inlet section, in particular, the greater the reproducibility of the measurement results. If
possible, the inlet section should be more than 20 times greater, and the outlet section 10
times greater than internal diameter of the duct (Di). With rectangular cross-sections, the
diameter is calculated as 4 times the cross-section divided by the duct circumference.
On existing installations, choose the optimum location.
If you are uncertain of the flow conditions, you should measure the profile at the measuring
location, for example, using pitot tube flow meters (see DIN EN 13284-1). Calibration aper-
tures must be provided for this purpose. The measurement axis must then be defined in
such a way that any changes in the profile will only have a minimum impact on the result of
the measurement.
If the FLOWSIC100 is to be used for official measurements (for example, emission measure-
ments pursuant to the Federal German Pollution Control Act), the measuring location
should be determined by a legally authorized expert (for example, by means of an expert ap-
praisal of a measuring location authorized in accordance with Articles 26 and 28 of the Fed-
eral German Pollution Control Act).
Fig. 3.1: Installing the sender/receiver units
Installation in short inlet section
Installation at inlet and outlet sections with sufficient length
Di
A
Duct/
pipeline
Inlet section
Flow distribution not
uniform downstream
of curvature
Uniform flow distribution
Sender/receiver unit
View A
Outlet section
To Next Page
Loading...
